Meanwhile, some of the promises offered by the campaigners to leave the campaign have been revealed as hollow — including by Nigel Farage, leader of the far-right UKIP party and campaigner for the referendum, who seemingly reneged on Vote Leave's promises to spend "£350 million a week" in cash supposedly bound for the EU on health care Friday.

"Brexit is probably just the beginning, as populist/separatist/xenophobic movements gain influence across the continent," wrote the New York Times' Paul Krugman "... Brexit just brings to a head an abscess that would have burst fairly soon in any case."

One word - #regrexit

It's enough to make 1.5 million people #regrexit, signing a petition with over 2.3 million signatures as of Saturday afternoon on the U.K. Parliament's official website. Some regret their decision, while others lament not voting.

"I didn't think my vote was going to matter too much because I thought we were just going to remain," one British man told the BBC.

"This morning the reality is actually hitting in and the regret is hitting in," student Mandy Suthi told the Evening Standard. "I wish I had the opportunity to vote again, simply because I would do things differently."

Just spoken to the first #Brexit voter who now, in the cold light of day, #REGREXIT He shall be nameless, and he won't be alone

I'm now hearing non-voters say they wanted to Remain but didnt bother voting as they were so sure we'd vote that way #regrexit

This will also be taken into account by the markets on Monday. Brace yourselves. #Brexit #Regrexithttps://twitter.com/andersostlund/status/746642326634766336 ...

According to CNN, the petition has passed the 100,000 signatures mark necessary to force a debate on the topic in Parliament. Since the Brexit vote was a non-binding referendum, the legislative body could technically refuse to follow through on it.

As CNN noted, the thresholds demanded by the petition would conveniently undo the results of Thursday's referendum, as only 51.9 percent voted to leave based on a turnout of 72 percent.

Some have mocked the campaign and the hashtag, suggesting British voters should have turned out in greater numbers to defeat the referendum if they cared about the future of the U.K.: